Roll back deprecation of multi-asset sensor (#26390)

Resolves #26223 

## Summary & Motivation

`@multi_asset_sensor` was deprecated with a message saying to use
`AutomationCondition`, but `AutomationCondition` cannot cover all of
`@multi_asset_sensor` uses cases (like running jobs), as discussed in
#26223.

## Changelog

Deprecation of `@multi_asset_sensor` has been rolled back.

python_modules/dagster/dagster/_core/definitions/decorators/sensor_decorator.py

@@ -4,7 +4,6 @@
 from typing import TYPE_CHECKING, Any, Callable, Mapping, Optional, Sequence, Set, Union
 
 import dagster._check as check
-from dagster._annotations import deprecated
 from dagster._core.definitions.asset_selection import AssetSelection, CoercibleToAssetSelection
 from dagster._core.definitions.asset_sensor_definition import AssetSensorDefinition
 from dagster._core.definitions.events import AssetKey
@@ -248,7 +247,6 @@ def _wrapped_fn(*args, **kwargs) -> Any:
     return inner
 
 
-@deprecated(breaking_version="2.0.0", additional_warn_text="use `AutomationConditions` instead")
 def multi_asset_sensor(
     monitored_assets: Union[Sequence[AssetKey], AssetSelection],
     *,